Editing Blueprint default values will make the level it is contained in get marked as dirty

When Blueprint default values are edited, those edits will also be propagated to any active instances in the level. Each edit event will mark the level as dirty.

Similarly, in a World Partition map w/ OFPA (one-file-per-actor), external Actor assets will also be marked dirty post-edit. This can lead to significantly large numbers of unsaved assets after a single default value edit, which can make developer workflow difficult.

Since default values are serialized to the CDO, and only per-instance edits are serialized to the level/OFPA assets, there is no need to dirty the level/OFPA assets after default value propagation, as they would not require saving.

This issue is related to [Link Removed], but is unrelated to Blueprint compiler workflow.

1. Launch UE editor (any project)
2. Create a new Actor-based Blueprint asset
3. Add a new variable (e.g. bool type), compile and save
4. Drag a new instance of the Blueprint into the current level and save (NewMap)
5. In the Blueprint editor, switch to "Class Defaults"
6. Change the value of the variable added above
7. Note that the level (NewMap) is marked dirty

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